s=input()
if any([s.count('c')<1,s.count('w')<2]):
	print(-1)
else:
	C=[i for i,v in enumerate(s) if v=='c']
	W=[i for i,v in enumerate(s) if v=='w']
	m=1000
	for c in C:
		tW=[i for i in W if c<i]
		if len(tW)>1:
			m=min(m,tW[1]-c+1)
	print(-1 if m==1000 else m)